Substrate flattening method and film-coated substrate made thereby

Abstract

The present invention provides a method of easily planarizing the uneven surface of a substrate having an uneven surface. This method comprises the steps of forming a coating film containing spherical fine particles on a surface of a smooth substrate; sticking the surface of the smooth substrate provided with the coating film containing spherical fine particles to the uneven surface of a substrate having an uneven surface; and transferring the coating film containing spherical fine particles to the uneven surface of the substrate so that the uneven surface is planarized.

What is claimed is:  
     
       1. A method of planarizing a surface of a substrate having an uneven surface, which comprises the steps of: 
       forming a coating film containing spherical fine particles on a surface of a smooth substrate;  
       sticking the surface of the smooth substrate provided with the coating film containing spherical fine particles to the uneven surface of the substrate having an uneven surface; and  
       transferring the coating film containing spherical fine particles from the surface of the smooth substrate to the uneven surface of the substrate having an uneven surface so that the uneven surface is planarized.  
     
     
       2. The method as claimed in  claim 1 , wherein the surface of the smooth substrate is first furnished with a layer of spherical fine particles, and followed by applying a coating liquid for film formation onto the layer of spherical fine particles to thereby form the coating film containing spherical fine particles. 
     
     
       3. The method as claimed in  claim 1 , wherein the surface of the smooth substrate is applied with a coating liquid for film formation which contains spherical fine particles to thereby form the coating film containing spherical fine particles. 
     
     
       4. The method as claimed in  claim 1 , wherein, at the time of transferring the coating film containing spherical fine particles to the uneven surface of the substrate having an uneven surface, or thereafter, 
       the coating film containing spherical fine particles is heated so that at least part of the coating film is melted to thereby planarize the surface of the coating film, and  
       subsequently, the temperature is further raised so that the coating film containing spherical fine particles is cured to thereby accomplish the planarization of the uneven surface of the substrate having an uneven surface.  
     
     
       5. The method as claimed in  claim 1 , wherein the spherical fine particles are fine particles of silica and the coating film is a coating film containing a silicon-based component. 
     
     
       6. The method as claimed in  claim 5 , wherein the coating film is formed from a coating liquid which contains a polysilazane having a repeating unit represented by the general formula [1]:                    
       wherein R 1 , R 2  and R 3  may be identical with each other or different from each other and represent a hydrogen atom, an alkoxy, aryl or alkyl having 1 to 8 carbon atoms, and n is an integer of 1 or greater.  
     
     
       7. A substrate with a coating film having its surface planarized by the method as claimed in  claim 1 . 
     
     
       8. A process for producing a semiconductor device, comprising the steps of forming a coating film containing fine particles of silica by applying a coating liquid containing a polysilazane having a repeating unit represented by the above general formula [1] on a surface of a smooth substrate; and transferring the coating film containing fine particles of silica to an uneven surface of a semiconductor substrate so that the semiconductor substrate surface is furnished with the coating film containing fine particles of silica. 
     
     
       9. The method as claimed in  claim 2 , wherein, at the time of transferring the coating film containing spherical fine particles to the uneven surface of the substrate having an uneven surface, or thereafter, 
       the coating film containing spherical fine particles is heated so that at least part of the coating film is melted to thereby planarize the surface of the coating film, and  
       subsequently, the temperature is further raised so that the coating film containing spherical fine particles is cured to thereby accomplish the planarization of the uneven surface of the substrate having an uneven surface.  
     
     
       10. The method as claimed in  claim 3 , wherein, at the time of transferring the coating film containing spherical fine particles to the uneven surface of the substrate having an uneven surface, or thereafter, 
       the coating film containing spherical fine particles is heated so that at least part of the coating film is melted to thereby planarize the surface of the coating film, and  
       subsequently, the temperature is further raised so that the coating film containing spherical fine particles is cured to thereby accomplish the planarization of the uneven surface of the substrate having an uneven surface.  
     
     
       11. The method as claimed in  claim 2 , wherein the spherical fine particles are fine particles of silica and the coating film is a coating film containing a silicon-based component. 
     
     
       12. The method as claimed in  claim 3 , wherein the spherical fine particles are fine particles of silica and the coating film is a coating film containing a silicon-based component. 
     
     
       13. The method as claimed in  claim 4 , wherein the spherical fine particles are fine particles of silica and the coating film is a coating film containing a silicon-based component. 
     
     
       14. The method as claimed in  claim 11 , wherein the coating film is formed from a coating liquid which contains a polysilazane having a repeating unit represented by the general formula [1]:                    
       wherein R 1 , R 2  and R 3  may be identical with each other or different from each other and represent a hydrogen atom, an alkoxy, aryl or alkyl having 1 to 8 carbon atoms, and n is an integer of 1 or greater.  
     
     
       15. The method as claimed in  claim 12 , wherein the coating film is formed from a coating liquid which contains a polysilazane having a repeating unit represented by the general formula [1]:                    
       wherein R 1 , R 2  and R 3  may be identical with each other or different from each other and represent a hydrogen atom, an alkoxy, aryl or alkyl having 1 to 8 carbon atoms, and n is an integer of 1 or greater.  
     
     
       16. The method as claimed in  claim 13 , wherein the coating film is formed from a coating liquid which contains a polysilazane having a repeating unit represented by the general formula [1]:                    
       wherein R 1 , R 2  and R 3  may be identical with each other or different from each other and represent a hydrogen atom, an alkoxy, aryl or alkyl having 1 to 8 carbon atoms, and n is an integer of 1 or greater.  
     
     
       17. A substrate with a coating film having its surface planarized by the method as claimed in  claim 4 . 
     
     
       18. A substrate with a coating film having its surface planarized by the method as claimed in  claim 5 . 
     
     
       19. A substrate with a coating film having its surface planarized by the method as claimed in  claim 6 . 
     
     
       20. A substrate with a coating film having its surface planarized by the method as claimed in  claim 14 .